Conventionally, various methods for displaying three-dimensional images have been proposed. Of these, “binocular methods” using binocular parallax are generally used. Specifically, a stereoscopic vision can be achieved by providing left and right-eye images having binocular parallax and projecting them separately on the left and right eyes, respectively. In the observation of three-dimensional images of this kind, the obtained stereoscopic effect depends on the magnitude of the binocular parallax (to be called “the amount of parallax”). Accordingly, if stereographs of an identical three-dimensional image are displayed in different sizes on screen, the resultant visions become different because of the change in the amount of parallax. That is, even when an identical display apparatus is used, the amount of parallax becomes greater if the display size of the image is enlarged. Further, on different display apparatuses, there occur cases where the amount of parallax becomes greater if the image is displayed on the display apparatus having a greater size.
FIG. 7 shows this situation, where w<W. In the case where, as shown in FIG. 7(a), a right-eye image 701 and a left-eye image 702 fuse into a stereoscopic image at a position 703, if the display size of the image becomes greater as shown in FIG. 7(b), the amount of parallax w in the case shown in FIG. 7(a) becomes greater and equal to W. As W becomes too large, it is impossible to see a stereoscopic view with both eyes. If the image is magnified by an image process, it is possible to predict the possibility of incapability of reproducing a stereoscopic vision because the magnification is done by the process on the terminal side. However, if the image is enlarged due to difference in the specifications between display apparatuses, there has been the problem that the situation cannot be correctly grasped.
In order to solve the above problems, a patent literature 1 has disclosed a technology in which three-dimensional image data is received together with information as to the size of the display apparatus that can produce a preferable stereoscopic effect if the three-dimensional images are supplied as they are, and the amount of parallax of the three-dimensional images is modified so that a preferred stereoscopic effect can be obtained in the user terminal display.    Patent literature 1: Japanese Patent Application Laid-open Hei 10-150608.